For a Hammerfell game: The player, as a mercenary of great renown and power, is invited by an excentric redguard nobleman hellbend on conquering Yokuda, to accompany him on his mission. On their way there a massive storm hits his fleet, resulting in the player being thrown over board. They wake up on a yokudan beach.
The storyline would be about helping either the sinistral elves, yokudans or colonists to take over Akos Kasaz from Vivec's demonic progeny that destroyed the yokudan remnants living on it centuries ago. Each faction would represent one class archetype:
The sinistral elves (controlling Yath, Akos Kasaz' south west coast and the two islands west of it) would reward the player with stone and sand magic as well as other goodies a wizard would like.
The yokudans (holding Akos Kasaz' east coast, Kanesh and the north of Samara) would give the player access to master smiths and legendary weapons.
The colonists (controlling the south of Samara, the small islands north and south of it and part of Akos Kazas southern coast) would offer items a thief or at least someone drawn to stealth and nonviolent stuff might enjoy.
At the end of the "main" questline the player and the factions would take over the former capital city and find out about the location of orichalc tower. The quest would culminate in a hunt for the ruins of orichalc tower where the player's faction would retrieve Penitent, the sword of Trinimac that served as orichalc's stone from the island far north of Akos Kazas. The sinistral elves will then decide to built a new orichalc tower to bend nature in its sphere of influence to their will.
The yokudans will gift it to their champion (the player) to lead them into one last battle with the colonists and elves to make them submit to their will.
The nobleman will pay the player in grand artifacts to give the sword to him and he presumably takes over all of Yokuda afterwards.
Sidequests could include talking to the ghost of the king Vivec created the children with, akaviri raiders attacking the western islands of yokuda and the player uncovering history since then forgotten like dawn magic or daedric artefacts trapped there, removed from the influence of their prince.